What is a Clapperboard anyway?

Take one! Clack! So what exactly is that board they smack shut just before calling “action” on a movie set?

It’s a part of filmmaking that most people have seen before but few fully understand its purpose. So here it is….

Syncing Images & Audio

First, the object in question is called a clapperboard or a slate board. Its first and primary purpose is to help filmmakers sync audio and sound. Often in Hollywood movies, the camera captures images separately from the the audio. Sound designers use a boom or lapel mics to record audio. To complicate things further, there could also be multiple cameras recording a single take. In post production, after filming has finished, the images and the audio need to be put back together. The Editor handles this task.

Cred: BENCO Motion Pictures LLC

To make the Film Editor’s job easier, it helps to have a way to synchronize the images and sound. This is where the clapperboard comes in. It’s nothing more than a piece of plastic (originally slate was used) with a wooden top and a hinge. Its construction allows the filmmaker to open the clapperboard before slamming it shut again, resulting in a sharp “snap” noise. This is done while both the cameras and audio are rolling (a film term for ‘recording’) resulting in an audio spike. The Editor can match-up the spike in sound wave with the moment the clapperboard shuts. Thus, the motion picture syncs up to the sound and the actor has their voice back again. Cool, right?

Organizing Raw Footage

The clapperboard also helps to organize film footage. Before each take, the filmmaker responsible for ‘slating’ (often the clapper loader or 2nd AC) will write on the slate. The relevant information includes the scene and take numbers, camera angle, date, production title and name of the director. Therefore the Film Editor, who may not be on set during production, knows exactly what he’s looking at when (s)he begins piecing together the final cut.

Cred: BENCO Motion Pictures LLC

Today, many larger productions have switched over to “digislates” or “smart slates.” These clapperboards display in LED an unique time-code that the audio recorder generates. The sound and audio sync up when someone flashes the board in front of the camera, then we are free to start rolling, no clap necessary.